(ˈ)är|sänik-, -sō- noun
Etymology: International Scientific Vocabulary arson ium + -ic
1. : any of a series of organic acids (as the arsanilic acids) having the general formula RAsO(OH) 2 and obtainable by oxidizing monosubstituted organic arsines (as phenyl-arsine C 6 H 5 AsH 2 )
2. : arsinic acid 1